Gasket material



Jan. 3o, 1945. H` B, DENMAN 2,368,118

GASKET MATER IAL Filed Jan. 6. v1943 Jarzzy l?, Benman Patented Jan. 30, `1945 GASKET MATERIAL Harry Detroit B. Denman, Detroit, Mich., assigner to Gasket & Manufacturing Company,-

Detroit, Mich.,l a. corporation o! Michigan. Application January 6, 1943, Serial No. 471,497

Claims.

The present invention relates to a compresslble, thermoplastic sealing or gasket material which is a satisfactory substitute for rubber and constitutes a substantial improvement over the same for sealing and otherl purposes.

The primary object of the invention is to provide a composition which may be prepared by milling' as in a Banbury mixer and sheeted after the manner of rubber, or extruded. From the sheeted or extruded products, there may be readily formed jar and closure seals, as well as gaskets for general application, having any desir'ed flange width and edge thickness.

An equally important object of the invention is to produce a sealing composition which is compressible, flexible and plastic but also is firm or semi-rigid in that it does not flow laterally under compression at normal or elevated temperatures in a manner to impair the seal and allow leakage to occur. at normal temperature and, more so, under heat and pressure, the sealing material readily conforms to the joint surfaces and the conforming seal ort is resiliently maintained at all times as distinguished from a weak, free-owing plastic composition.

Anotherobject of the invention is to provide a composition including constituents which contribute the compressibility and plastic characteris'tics and constituents which cooperate to raise the softening point and tensile strength, whereby when compressed, the composition is prevented from unrestrained flow laterally, but on the contrary is resilient and self-sustaining.

An additional object of the invention is to provide a sealing material which may be economically produced and which will aord a seal having a long-er life than rubber compounded products.

In the accompanying drawing, I have illus- Thus, under pressure trated several embodiments of the invention, and

it is to be understood that the sealing material may be produced in any shape or lsize necessary for various types of closure seals and gaskets'. Referring to the drawing, Figure 1 is a plan/view of a sheet of the sealing materiak" f Figure 2 is a plan view of a jarring formed from the sheet material;

Figure 3 is an elevationof a tube of the sealing material which has been extruded and from which gaskets of any required flange width and edge thickness may be cut; and v Figure 4 isa sectional view showing the sealing compound applied to a backing of paper,

vegetable oil a sheeting quality characteristic of milled rubber andnot obtainable with the vulcanized corn oil alone becausethe latter is of a crumbly character and not susceptible of satisfactory sheeting. The blown asphalt and vulcanized oil provide desirable compressibility and plastic properties of the composition.

The gilsonite impartsvhardness to the material, i. e., raises the softening point of the thermoplastic final product. The combination of the petroleum resin and the vulcanized vegetable oil forms a weak free flowing plastic mass tooysoft and with too little resistance to pressure at normal temperature. The presence of the gilsonite assures that the material when subjected to pressure will not ow laterally unrestrained at normal temperatures. f l

After the three materials above mentioned have been suitably blended in the Banbury or other -mill, there is added successively or simultaneously a filler or libres such as short asbestos libres (grade 3-b), a wax such as parain wax and a pigment such as red iron oxide or Titanox or a mixture of the two. Instead of such a pigment there may be included an absorbent-pigment for deodorizing the sealing material of which charcoal in finely divided form has been found highly suc- The fibres, wax and color are milled into the batch until all three have been thoroughlyfincorporated. As will be appreciated, the inclusion of the pigment is optional.

vThe purpose of the mineral illler is to resist lateral flow and particularly by increasing the tensile strength of the composition. The gilsonite, as stated above, resists flow .under normal temperature, but does not impart in itself sumcient tensile strength.- In other words, the gilsonite increases the softening point whereas .the mineral filler resists flow because of thetensile strength imparted by the mechanical interlocking of the vilbres in thev mixture and is particularly effective under pressure at elevated temperatures.

The wax imparts a slippery surface which is useful during calendering or extruding and assists in the blending of the other materials during the milling. In the nal product, the wax blooms at the surface, thereby preventing objectionable sticking of the sealing material, for instance, to the lip of a container.

By compounding materials having characteristics above described and in suitable amounts, a sealing material is produced which is an effective substitute for rubber and possesses improved properties thereover. The material of the present invention, as stated, is thermoplastic, highly compressible, and possesses tensile strength and resistance to flow under pressure at normal and elevated temperatures. Therefore, whether used in association with a closure or as a gasket generally, it precludes leakage by providing a tight resilient seal having along life.

The following is a preferred example which has been found to possess highly acceptable attributes for sealing purposes.

Example Percent Petroleum resin about to 20 Processed vegetable oil (probably absolute minimum) about to 50 Mineral resin about 10 to 25 Mineral fibre about 25 to 50 Wax about lto 8 In addition, if desired', colors or pigments may be incorporated in amount up to about 10% and where a nnely divided absorbent-pigment such as charcoal is used, this may be employed in amount up to about 15% and has the additional function-of deodorizing the sealing compound.

After the constituents of the mixture have been suitably incorporated and blended, the composition is sheeted or slabbed from the mill in the usual manner of rubberand calendered, or it may be extruded. A sheet of the material is indicated in Figure 1 at I 0 from which may be out gaskets of any suitable shape and size, for instance, Mason jar rings, as illustrated in Figure 2 at II. The sheet may be of any desired thickness to control the thickness of the gasket or ring.

As an example of an extruded product made from the sealing composition, reference is had to Figure 3 wherein the tube I2 is extruded and the thickness of the same will correspond to the desired flange width. From this tube may be severed gaskets or rings I3 of lany desired edge thickness, similar, for example, to the rings II.

In some cases, it is desirable to provide a laminated product including the sealing material of this invention as shown in Figure 4 wherein the numeral I4 indicates a backing of paper, metal or synthetic resin upon which is disposed a layer of any suitable thickness I5 of the material of this invention.

I claim:

1. A sealing material comprising blown plasticized paraflin base oil asphalt about 10 to 20%, vulcanized corn oil about 15 to 50%, gilsonite about 10 to 25%, short asbestos iibres about 25 to 50%, and parain wax about 1 to 8%.

2. A closure seal or gasket prepared from a material comprising blown plasticized paraffin base oil asphalt about 10 to 20%, vulcanized corn oil about l5 to 50%,V gilsonite about 10 to 25%, short asbestos fibres about 25 to 50%, and paraffin Wax about 1 to 8%.

3. A jar ring prepared from a sealing material comprising blown plasticized paraffin base oil asphalt about 10 to 20%, vulcanized corn oil about 15 to 50%, gilsonite about 10 to 25 short asbestos bres about 25 to 50% and parailln wax about l to 8%.

4. A sealing material comprising blown plasticized paraffin base oil asphalt about l0 to 20%. vulcanized corn oil about 15 to 50%, gilsonite about l0 to 25%, short asbestos bres about 25 to and paraffin wax about 1 to 8% and pigment up to about 15%.

5. A sealing material comprising blown plasticized paraffin base oil asphalt about 10 to 20%, vulcanized corn oil about 15 to 50%, gilsonite about 10 to 25%, short asbestos fibres about 25 to 50%, and parain wax about 1 to 8%, and an absorbent material for deodorizing the composition up to about 15%.

HARRY B. DENMAN. 

